To facilitate proper navigation, many mobile wireless devices use on-board global positioning system (GPS) technology. GPS technology allows each mobile wireless device to calculate its geographical location by communicating with satellites or other reference points, such as, for example, wireless base stations. However, for those mobile wireless devices that do not have a GPS component or other method of determining geographic location, useful mobile services are severely limited. In addition, even in phones with GPS capability, devices may frequently have their location determination capabilities interrupted by so-called “urban canyons” or other obstructions.
To address these problems, systems and methods have been determined for enabling a cell phone to estimate its geographic location without having a GPS component, embodiments of this being described by Ji et al. in U.S. patent application Ser. No. 12/323,921, filed Nov. 26, 2008, entitled “Systems and Methods for Estimating Location Using CID and Application Specific Data” which is incorporated herein by reference in its entirety (hereinafter “'921 Application”). Knowing the geographic area corresponding to the minimum radio coverage of a cellular site may increase the accuracy of this non-GPS location estimation. As used herein, cellular sites correspond to cell site, wireless base station, base station, cellular transceiver, cell antenna, cell tower and other like terms known in the art. As used herein, a cellular sector corresponds to cell, cell sector, cell zone, wireless coverage area, service area, coverage region and other terms known in the art describing the radio coverage area of a cell site.
Information regarding the geographic coverage area of various wireless base stations is usually only available to mobile service providers that operate the wireless base stations or other related entities. Further, even mobile service providers may not have knowledge of the geographic coverage area of many wireless base stations outside of their own networks.
Many different approaches exist to determine the coverage area of cellular sites, but these approaches are generally only able to be performed by the cellular service providers, and are generally based on non-public, physical characteristics of the cellular site. Current approaches to estimating cell site minimum coverage area rely upon certain physical characteristics of the cell site, including the cell site's precise location, elevation, antenna height, antenna azimuth angle, sector beam width and transmission power. Generally, these physical characteristics and the determined minimum coverage information are not made available to the public.
For at least these reasons, it has been difficult to get complete information on the coverage area of various cell sites. Estimated geographic wireless coverage information is needed for any geographical region of interest regardless of which mobile service provider is providing coverage.